1. Field
One or more exemplary embodiments relate to a field emission device and a method of manufacturing the same.
2. Description of the Related Art
Field emission devices emit electrons from emitters formed on cathodes by forming a strong electric field around the emitters. Such field emission devices may be representatively applied to field emission displays (“FEDs”), which display images by the collision of electrons emitted from a field emission device with a phosphor layer formed on anodes, backlight units (“BLUs”) of liquid crystal displays (“LCDs”), and the like.
LCDs display images on a front surface thereof by passing light, generated from a light source installed on a rear surface, through a liquid crystal layer which controls light transmittance therethrough. Examples of the light source installed on the rear surface of the LCD may include a cold cathode fluorescence lamp (“CCFL”) BLU, a white light emitting diode (“WLED”) BLU, a field emission BLU, and various other similar devices. The CCFL BLU provides color reproducibility and is manufactured at low costs. However, since the CCFL BLU uses the element mercury (Hg), the CCFL BLU may pollute the environment and may not increase brightness and contrast. The WLED BLU is dynamically controlled, however it incurs high manufacturing costs and has a complicated structure. The field emission BLU is locally dimmed and impulse/scan-driven to thereby maximize brightness, contrast, and the quality of motion pictures. Thus, the field emission BLU is expected to become widely used as a next-generation BLU. The field emission devices may also be applied to other various systems using electron emission, such as, X-ray tubes, microwave amplifiers, flat lamps, and other similar devices.
Micro tips formed of metal such as molybdenum (Mo) have been used as emitters which emit electrons in a field emission device. However, in recent years, carbon nanotubes (“CNTs”) that provide good electron emission characteristics are becoming more widely used as emitters of a field emission device. Field emission devices using CNT emitters are driven with a low voltage, and have good chemical and mechanical stabilities.
Since such field emission devices are currently manufactured by performing photo patterning and firing several times, the manufacturing thereof is complicated and incurs heavy expenses. More specifically, metal electrodes such as cathodes may be roughly formed in two ways. In the first way, chromium (Cr), molybdenum (Mo), or the like is deposited by vacuum deposition and then patterned by photolithography. In the second way, silver (Ag), or other similar elements, is stencil-printed and then fired. However, the first method requires vacuum deposition equipment and is complicated, and in the second method, an expensive material is used, and thus, field emission devices are manufactured at high costs.